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Post by dralyagmas on Aug 15, 2014 4:47:07 GMT
I am looking for advice. My 2003 SunFast 37 is basic. I have replaced the battery bank with 3 x 130aH AGM (House) and 1 x 130Ah (motor). I have charging via the motor when ins running but I am looking for alternative power supplies to keep the batteries charged when away for anything up to a fortnight.
My boat currently does not have a dodger or bimini to house solar panels at this stage (they will come). It also does not have microwave or other high output appliances
The options I am considering: 100-120W flexible solar panel on the coach roof same as in the hints and tips section + good MPPT regulator. - I live in a high sun location (South Australia) and they will always be charging but will be shaded when on certain points of sail. Cost ~$600 Fold out hard solar panels @ 240W on the same coachhouse roof, MPPT regulator. - May not be folded out all the time but area significantly greater than single flexible panel Cost $600
Wind generator Where I live is also windy in summer but not so much in winter ~$1500
Generator pain in the rear, hard to store, noisy ~$1000 1 kVA ~$2000 2 kVA (is there a big difference if I am only charging batteries not running high output appliances)
Obviously I don't want to spend heaps and my ultimate aim is to have 2 x 100W solar on a dodger as well as wind. If I need extra then I would go to a generator in the long term if I have to. But I can see advantages in going for a generator sooner as it would give me a guarantee of power rather than only solar or only wind.
How much solar do you think I would need? I have seen people talk about 400W but others only have 80W...
Any input would be appreciated particularly previous experiences with any or all of the above
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Post by sailbleu on Aug 15, 2014 8:20:57 GMT
Dralyagnes,
I have all the above and still run low on energy , but then again i' m a greedy person ( my family are partners in crime) when it comes to power consumption. My 2 fridges will take more than 100 amps daily. I have around 700watt solar (piek and in theory that is) and occasionally , on windless days , i run low on energy. But i admit , i very very rarely run the engine for power be it never. I' m anchored up on the windy coast of Corsica right now and i see my air breeze windgenerator supplying up to 25 amp (during gales) Check ebay for air breeze windgenerator and you'll be spending half on what you mentioned. I also like my cheap 2800 watt invertor Kipor generator though , 20 minutes to bake sandwitches in my AC oven , run a hairdryer , a watermaker , charge batteries , whatever. I guess it all has to do with the degree of autonomy you wish to keep up.
If you want to be prepared to exceptional circumstances ,.... Clouded days , no wind and only anchorage , you will need additional energy supplies. It's that simple. But maybe it will depend on where you stay , in Italy you pay (40 feet ) minimal 60 euro and 4 years ago i've paid up to 120 euro for one night.
Regards
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Post by rene460 on Aug 15, 2014 9:52:34 GMT
Hi dralyagmas,
You did not say what loads you want to run, which is basic to the solution. To me, it all depends on whether you want to run a fridge, the next biggest load can be nav lights if you sail overnight. It is easier to run cabin lights, radio, and charge the iPods as most of these only run a few hours each day. Changing as many lights as possible to LED helps to reduce the power needed.
Also for two weeks, batteries help you run overnight and for one or two cloudy days, but not for two weeks, so you need to cover 25-50% more than your daily needs. Battery charging is not 100% efficient and you need to store some for the cloudy days. I have only one 55 watt panel and at 38 deg South, we can run several days if we turn off the fridge at night and minimise lights, TV etc., but we are definitely running the batteries down and two cloudy days means a trip back to the mains supply, or at least a motoring trip. We have about 220 Ah of house battery capacity. I avoid running the motor just for battery charging, though as a last resort, and at hours which do not annoy others too much.......
To run a fridge plus basic lighting and radio, I would suggest that you might need two of those flexible panels, one each side, with separate isolation diodes, so at least one works most of the time. After a season or two, you will know if it is enough, or if you need a fold out to back up. If you decide on a generator as a last resort, look at whether your batteries can really accept the potential charging output of the larger unit, I suspect it would only be needed to run a microwave or other large appliances, does not sound like your basic essentials on a Sunfast, the smaller one is probably enough for typical charging rates.
rene460
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Post by dralyagmas on Aug 15, 2014 22:11:03 GMT
I have changed all lights inside and out to LED and we do run the fridge as much as we can (standard issue built in). If the weather is not too hot then we will turn the fridge off over night and I have a wireless thermometer for both the fridge and freezer to ensure that we are not going too high. We currently don't have a TV but it's on the cards as we cruise with a 6 and 3 year old. I try to be as scrupulous with power as I can as we don't run any AC appliances, definitely no hairdryers. All cooking is done with the gas
To be able to fit two of the flexible panels on the coach roof I will need to make up a fibreglass cowling that goes across the sliding hatch, which is not an issue but I didn't think of it needing to go wider than the slides. I was anticipating making one that just went longer.
i might borrow a portable foldout panel for our next trip and see how much we use and how much it charges before we commit to modifying the boat too much. I also might start scouring eBay for wind generators or a small generator.
thanks
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Post by sailbleu on Aug 16, 2014 6:10:52 GMT
Again , do not expect too much of solar energy . Unless you pack your boat with panels you will not sustain on the supply of a few panels only. Alot of people tend to overestimate solarpanels. I too have a tv and harddisk- mediaplayer to entertain the kids , be it a fairly big lcd screen , watching 2 hours of tv cost me more than 20 amps. And then there are the electrical toilets , man . You dont need all these gadgets , but we like some luxury on board , to a certain extent that is. Led lights in and out is a very good start , and if you install a dimmer (also see H&T section) you save even more. Charging the batteries using the engine will take hourrrrrrrrrs , also a misunderstanding . It's not because you have 60 ,80 or a 100 amp alternator that these figures are the loading charge. No way ! Same thing for the batteries , a rule of thumb is you have access to 50% of the battery capacity, then it stops for most types of batteries. I can go on , but the thing for a pleasant continuous stay on board is , you'll be needing several worlds/types of energy supply. Or run the engine all the time , .....which i personally detest.
Regards
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Post by saxofon on Aug 16, 2014 7:15:46 GMT
Gosh, some peoples boats are like a smaller power plant! :-) My boat (SO37.1) have two solar panels, each 33W. Fixed montage on roof. I never use any shorepower and go for motor only when going in/out. My fridge (I think it is standard although it is really huge, loads of beers go into it and it is not even half full ) draws like 6A max but that is only for shorter periods, perhaps something like 2-3A per hour. And yet it is 1-2 degrees only with regulator set to lowest, cannot get it lower unfortunately. would like it to be like 4-5 degrees or so. Can probably make a freezer out of it if I put it to max Except for fridge, there is also a smaller server running and a internet router. Together they only contribute like around 0.6A so it is very small. These are the stuff running all summer. 4 people, audults, onboard for a week with phones, pads etc to charge and the batteries is still going strong. I have 3 x 110Ah AGM in house bank and 80Ah AGM in motor bank. Have changed two spotlights to LED, rest is still the powerhungry original lights. Location is Sweden/Stockholm. We do have quite good amount of day hours during summer which is when I'm using my boat most, like 3-5 weeks. Other times it is weekend sailings only. There is a lot of parameters into the energy equation I think, usage patterns, location, gadgets etc etc. For me 2x33W is enough, for sailblue 700W seems not. I believe I would also like something like that if I would go on longer trips.
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Post by hoppy on Aug 16, 2014 10:46:26 GMT
I have 3x110ah house and 110ah starter batteries. I have 2x100w solar panels. The boat is based in Greece and only used over summer, so there is plenty of sun. I run the fridge on full power or 1 stop under all of the time but have fitted LED throughout. When I sail day time and anchor overnight , so far I have not needed to run the motor to charge up the batteries. When I did a 2 night passage I did find that the overnight usage of nav lights, radar etc did require me to run the motor to boost the batteries. I have since changed the nav lights to LED which if I recall should save about 1amp. Personally I don't like the idea of solar on the bimini or dodger as on hot days I don't use the dodger and if I want to enjoy sail trim I drop the bimini. Of course others wont like my arch solution ;-) You could look at mounting the solar panels on the pushpit I cannot imaging fitting a generator on my SO40 as I think it takes up too much space. I would rather go the fuel cell route www.efoy-comfort.com as they are compact, quiet and can be mounted inside the cabin, but they are expensive and depending on where you want to sail, the fuel may be difficult to source, but that is not an issue if you are just going to do 2 weeks trips out of SA At some point I may look to add an alternative to Solar to boost the charging but not sure if I will go for wind or maybe fuel cell
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Post by rene460 on Aug 16, 2014 11:12:42 GMT
Hi dralyagmas,
I would certainly go for the TV for the kids, but like me, you are probably in a fringe reception area, so you need a good powered aerial, and a DVD slot for when you are out of range. You also need a set that is easy to retune. On the Gippsland Lakes we need to retune if we shift as little as 15 miles, on the Gulf I assume that you will travel further than that with a similar transmitter spacing.
You can see there is a great range in what people find they need and what they achieve. I have found that I can do all the calculations I like, but in the end it amounts to whether can I maintain my battery voltage, or do I need more panels. But more panels allow some to face each direction so at least one is in a more favourable location, and will not often all deliver their maximum potential power at the same time. The calculations usually rely on the panel rating which is given in Watts but in effect the current does not increase much when you go to a lower voltage as the formula would indicate, they behave more like a constant current device, but a MPPT device is supposed to maximise what you get. Also the rating is usually assuming 1000 W/m2, with the panel facing square to the sun. A horizontal panel gives more than one facing the wrong way, and even with an adjustable mount, there is a limit to how often it will be adjusted. The shadow of a shroud on a panel can drastically reduce a panel output. You have shorter days than Stockholm and I suspect warmer air temperatures (so your fridge will run for more hours each day), but saxofon certainly shows what can be achieved with care and is interesting for illustrating the advantage of really long days. Cloud cover is also a big factor. In the end you get what you get. A wind generator helps, but panels make less noise when you have plenty of sun as an alternative.
I am sure we all look foreward to hearing how you go.
rene460
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Post by dralyagmas on Aug 16, 2014 11:27:24 GMT
Thanks everyone for the replies. It does highlight the vast differences in set ups and operating conditions.
food for thought. I think some panels might be in order but I might try out a few arrangements before buying.
i think the TV will come soon, the kids on the laptop works well as we can stick them in a berth with a movie so we can sit and entertain in the main cabin. I will talk around the club about how often we would have to tune it but the hard drive is likely to do most of the work. Plus I am keen go get them outside if the weather is good.
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Post by rxc on Aug 16, 2014 17:19:22 GMT
I think you are going about this the right way - listing all the stuff that you want to be able to do on the boat, listening to other people and how they deal with the loads, and if you can, looking at actual installations on other similar boats.
I started down this path with my old boat when my wife said that she wanted to be able to re-heat her tea(!). Since tea cannot be re-heated on the stove, it requires a microwave, which requires an inverter, large batteries to power the inverter, new cables, an upgraded alternator for charging while underway, etc. Once that was done, we had an experience where we were stuck in a creek for two days waiting out a hurricane and my wife was unhappy that we had to run the engine to recharge the batteries, so this led to a large solar panel and a windmill, and all the associated hardware to mount them and wires/controllers/switches/monitoring devices to make them work.
When I bought my 43DS, I had 8 years of experience with the old system, and now I have a boat with 4 golf cart batteries, a high-output alternator and regulator, separate inverter and battery charger, two large solar panels and a windmill mounted on the arch, a 6 kW genset which has its own starting battery, engine starting battery, and another battery in the bow for the windlass and thruster. Plus all the associated wiring/switches/monitoring devices/etc. My wife cannot run any of it, and I have even been known to mistakenly leave both the battery charger and the inverter running at the same time (not good). So there is a downside to added capability.
You have to think ahead about what you might want to add in the future, and how you want to use the boat and where you want to use it. Maybe a simple 1kw portable genset that you can store in a locker would be sufficient. They are relatively quiet and can power any non-heating loads on the boat. And if you already have an outboard engine for a dinghy, you are already carrying gasoline for the genset, as well. If you eventually want to have air conditioning at anchor, you will need some serious generating power, and a 37 is in the size range where on-board AC starts to become more of a need than a want.
Of course, you could go simple now, and wait for the day when you wife tells you that you need to buy a bigger boat...
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Post by rxc on Aug 16, 2014 17:22:50 GMT
Oh, one last thought. Right now my boat is in a marina, plugged into shorepower that is powering the AC. However, I do not have the battery charger running, because I think it may be overcharging the batteries, so I just let the solar panels and windmill take care of DC loads, which are just the fridge and occasional lights. The batteries cycle about 10% each day, which I don't think is too bad.
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Post by so40gtb on Aug 17, 2014 21:54:58 GMT
We've been out cruising for 12 days now with Voyageur's new electrical system. Two Renogy 100W solar panels are temporarily attached atop the bimini, with a MPPT controller between them and the 420Ah AGM house battery bank. All lighting is LED but for the anchor light (need 2 reasons to go up the mast, not one). We find that we deplete 0 net Ampere-hours from the battery bank during mostly-sunny daylight hours, even with the refrigerator enabled and all the navigation instruments and chart plotters running. I can't yet address replenishment of overnight depletion because we haven't anchored out (Admiral insists on marina use if one is available, then insists on using the head aboard rather than walking up the dock to the facilities ... go figure!).
Voyageur's new radar, to be installed this winter, will be on her mast, so that will leave space open on the stern-mounted radar tower. Eventually, I'll likely add a wind generator there, to help keep charge up overnight during long cruises away from marinas (or in avoidance of slip rental fees).
--Karl
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Post by dralyagmas on Aug 21, 2014 3:23:34 GMT
OK it would appear that I don't have the funds to install solar at the moment as this should be done on top of the dodger. So I would need a dodger first. Therefore the cost goes past where I can afford until I sell my sportsboat. So as a temporary arrangement I am thinking about buying a petrol generator.
Honda seem to be the ducks nuts so the choice then comes down to size. Eu10 @ 1000W or Eu20 @ 2000W. Obviously the eu20 would be better for battery charging but its much harder to store on the boat. What would the real life effect of going for the 1000W instead? Will this mean that topping up the batteries one hour a day will turn into 4 hours a day?
I cant see us running appliances off it while charging so really its only for keeping the house batteries topped up.
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stack
Junior Member
Posts: 24
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Post by stack on Aug 26, 2014 13:35:19 GMT
My son has a Honda and he often is on hook, and he has more that he needs in power. keeps his batteries up and on hot knights runs his air conditioner. It is small and runs quiet. I know if I keep telling him how nice it is, he just may get one for his father for Christmas.
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Post by electricmonk on Aug 28, 2014 7:01:59 GMT
We spend months cruising around the coast of Turkey and the Greek Islands, currently the ambient temperature is 45deg sea temperature 32deg and there’s no wind. Under these conditions the fridge is the power user. We won’t put up with warm beer or no ice in the gin so it has to be cold. It has a keel cooler to eliminate the fan load and the insulation is as good as we can get it but even so it draws 4.5 amps – all day and all night. So the night load is a hefty 54amps plus lighting and water pumping, or around 70amps; about the useful capacity of an 80% charged 200 AH battery. So in daytime charging we need to find a minimum of 140amps plus all the losses from the charging process so its around 180 – 200 amps – spread over (say)12 hours is around 17amps per hour – its about now you realise that this rate of charge is getting close to the maximum absorption rate of a 200ah lead acid bank and probably not achievable regardless of what you use as a charger. So you must increase the bank size, but not by much or you get other problems like in practical terms you will never get it charged unless it’s permanently connected to shore power.
Solar could provide this load, you would need about 300watts of panel then you could operate when daylight is less than 12 hours. Wind gen – forget it. Diesel or petrol generator and a multistage 25amp charger would be useful to get you out of a fix. Main engine alternator would need to be at least 60amps, 80amps would be better but no bigger or you get more interesting problems to solve.
Petrol generators are OK but the fuel is not easy to keep safely, and they must be run the open so they cool.
We use a bit of solar - 80watts and a 4KVA diesel generator and the on board 50amp charger, but while the genny is running we run a 240v water maker to replenish the tanks so it all "works".
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Post by dralyagmas on Aug 28, 2014 9:11:32 GMT
Wow is that normal for a fridge? On the weekend I had the fridge on all the time and my battery monitor would say about 5.2 (total amps being used so included stereo) then when the fan switched off it would read 1.2. This switches back and forth but over 24 hours we used about 46 amps which included an old tungsten anchor light and an LED anchor light as well (steaming light but I put it on anyway to light up the boat a bit more when we anchor in this location).
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Post by electricmonk on Aug 28, 2014 9:37:45 GMT
it all depends on ambient and sea temperatures. I have quoted the current situation here in Turkey now. That's about as bad as it gets, though we have seen 55 deg some years. Most of the boats we see don't have cold beer and don't have ice and at the same time claim to have fully charged batteries and a cold fridge, sadly boats and batteries don't defy the laws of physics. When the temperature drops to 30deg our fridge is only on 50% of the time.
But what you are doing is right, find out what your load requirements are then provide plant that will exceed it by around 50% and you shouldn't have any trouble.
Remember that its very difficult, nay impossible to get batteries much more than 85% charged unless they are under no load and connected to a shore power charger for a week so reckon on not being able to get much passed 80%.
Its all about absorption rate and how this diminishes over time as the battery reaches 80 - 85% charged, smart chargers cant buck this fundamental property of lead acid cells. You could buy AGM batteries they are a slight improvement when bulk charging but the cost is high and you have to change/modify every piece of charging equipment to suit them - and you will still have to find the same number of amp hrs from somewhere so in my opinion nothing much to be gained for a huge outlay.
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Post by electricmonk on Aug 28, 2014 9:45:03 GMT
Just re - read your original post, you already have AGM batteries, so you must be sure to charge these properly - follow the makers requirements.
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Post by chuckr on Oct 8, 2014 17:50:51 GMT
Not sure this is still relevant but can only tell you what works for us. We have been out 7 years. We sail a DS 40 and have 6 6 volt batteries as our house bank with 3 solar panels for 400w of power with a blue sky controller. The panels are mounted over the bimini. We did not put on wind as the cost benefit trade off just was not worth it in our opinion.
We use to have a 150 amp alternator on our engine as a back up but in the Caribbean an electrican made a mess of it and we have been fighting with it for 3 years and finally had enough and will put on an 80amp alternator with internal regulator. By the way we put on the 150 when we got the boat and had no solar. By the way i have room for one more solar panel and if i can find it will add it.
In general if we do not go hog wild the solar does a great job of keeping the batteries up. We spent a bit of time in the San Blas islands of Panama and used only solar there until we had 21 days straight of no sun all clouds and alternator earned it keep.
We are currently in the Med and the solar does a good job for us here but we do not have a bunch of kids on board and watch or energy use.
Good luck in your design
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